43' Sunsation Discolored Exhaust Pipes
03-04-2021, 05:52 PM
#1
43' Sunsation Discolored Exhaust Pipes
Still looking at that Sunsation F4 and looking for some advice.
The straight pipes from headers to transom on the forward motor are discolored on top on both sides, not just normal tarnish. Boat has been idled for over 460hrs. I suspect the discoloration is a normal consequence of so many hours at idle which causes lower flow to exhaust jackets so they don't fill all the way and get hot on top.
Anyone else with an explanation?
Pic of discoloration on one side can be seen here:
The straight pipes from headers to transom on the forward motor are discolored on top on both sides, not just normal tarnish. Boat has been idled for over 460hrs. I suspect the discoloration is a normal consequence of so many hours at idle which causes lower flow to exhaust jackets so they don't fill all the way and get hot on top.
Anyone else with an explanation?
Pic of discoloration on one side can be seen here:
03-04-2021, 06:39 PM
#2
Registered
The tailpipes wouldn’t overheat like that from idling alone. My guess is at some point a sea strainer or something else was clogged and there wasn’t enough water flowing through everything. How do the headers look? Were they replaced at some point? I’d talk to someone at CMI about the tailpipes and see what they say. Usually it’s the headers that get hot and then fail.
Is that discoloration also in the starboard header of the starboard motor?
Is that discoloration also in the starboard header of the starboard motor?
03-04-2021, 07:50 PM
#3
What you see in the star side of the star header is a reflection. The headers are not discolored. There are just spots on top of those straight pipes that you can see in the pictures.
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ar300johnson (03-04-2021)
03-05-2021, 08:33 AM
#4
Forum Regulator
VIP Member
You need to get some information on the maintenance of the headers and those extension pipes.
The staggered engine boats have have issues with those forward motors due to the vibration of those long tail pipes and headers, as the vibration leads to cracks. That's why you see on some of the other boats and race boats have custom made sanctions to support those headers and tails where they join directly at the back of the engine.
Everyone knows the story with CMI headers and Mercury. CMI gets a bad wrap because Mercury specs a production header for CMI to manufacture and provide that's only designed to last as long as the warranty.
CMI's replacement products are MUCH better.
If it were MY boat, and it was time to spend some money on such, I'd go with https://www.stainlessmarine.com/prod...ers-tailpipes/
Sure they are not as pretty. But they do not suffer the vibration and leak issues that kill heads and motors. Many folks with 500s, 525s, 600s, 700s, AND bigger have gone to the SM manifolds with little or no performance difference; maybe loss of 1 or 2 mph top end in far outlier instances; usually none.
The staggered engine boats have have issues with those forward motors due to the vibration of those long tail pipes and headers, as the vibration leads to cracks. That's why you see on some of the other boats and race boats have custom made sanctions to support those headers and tails where they join directly at the back of the engine.
Everyone knows the story with CMI headers and Mercury. CMI gets a bad wrap because Mercury specs a production header for CMI to manufacture and provide that's only designed to last as long as the warranty.
CMI's replacement products are MUCH better.
If it were MY boat, and it was time to spend some money on such, I'd go with https://www.stainlessmarine.com/prod...ers-tailpipes/
Sure they are not as pretty. But they do not suffer the vibration and leak issues that kill heads and motors. Many folks with 500s, 525s, 600s, 700s, AND bigger have gone to the SM manifolds with little or no performance difference; maybe loss of 1 or 2 mph top end in far outlier instances; usually none.
Last edited by Sydwayz; 03-05-2021 at 08:49 AM.
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03-05-2021, 08:43 AM
#5
Registered
If it were MY boat, and it was time to spend some money on such, I'd go with https://www.stainlessmarine.com/prod...ers-tailpipes/
Sure they are not as pretty. But they do not suffer the vibration and leak issues that kill heads and motors.
I had headersaches for years till I got me some them Stainless marine units.
Pretty sure my headers looked like that after a lost a water pump belt . They were so hot I thought the boat was going to catch fire.
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poulsen11@yahoo. (03-05-2021)
